Mon, 25 Mar 2024 17:14:56 +0100
Brought the retry attempts to read the DHT11 sensors to the main devices loop. The actual read function is now very simple. Called every 30 seconds when all is well, or 2 seconds if something is wrong.
/***************************************************************************** * Copyright (C) 2014-2020 * * Michiel Broek <mbroek at mbse dot eu> * * This file is part of the mbsePi-apps * * This is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the * Free Software Foundation; either version 2, or (at your option) any * later version. * * mbsePi-apps is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with ThermFerm; see the file COPYING. If not, write to the Free * Software Foundation, 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. *****************************************************************************/ #include "lock.h" #include "thermferm.h" /* * Put a lock on this program. */ int lockprog(char *name) { char *tempfile, *lockfile; FILE *fp; pid_t oldpid; tempfile = calloc(PATH_MAX, sizeof(char)); lockfile = calloc(PATH_MAX, sizeof(char)); snprintf(tempfile, PATH_MAX, "/var/run/%s.tmp", name); snprintf(lockfile, PATH_MAX, "/var/run/%s.pid", name); if ((fp = fopen(tempfile, "w")) == NULL) { syslog(LOG_NOTICE, "Can't create lockfile `%s': %s", tempfile, strerror(errno)); free(tempfile); free(lockfile); return 1; } fprintf(fp, "%10u\n", getpid()); fclose(fp); while (TRUE) { if (link(tempfile, lockfile) == 0) { unlink(tempfile); free(tempfile); free(lockfile); return 0; } if ((fp = fopen(lockfile, "r")) == NULL) { syslog(LOG_NOTICE, "Can't open lockfile `%s': %s", tempfile, strerror(errno)); unlink(tempfile); free(tempfile); free(lockfile); return 1; } if (fscanf(fp, "%u", &oldpid) != 1) { syslog(LOG_NOTICE, "Can't read old pid from `%s'", tempfile); fclose(fp); unlink(tempfile); free(tempfile); free(lockfile); return 1; } fclose(fp); if (kill(oldpid,0) == -1) { if (errno == ESRCH || errno == EPERM) { syslog(LOG_NOTICE, "Stale lock found for pid %u\n", oldpid); unlink(lockfile); /* no return, try lock again */ } else { syslog(LOG_NOTICE, "Kill for %u failed: %s",oldpid, strerror(errno)); unlink(tempfile); free(tempfile); free(lockfile); return 1; } } else { syslog(LOG_NOTICE, "Another %s is already running, pid=%u", name, oldpid); unlink(tempfile); free(tempfile); free(lockfile); return 1; } } } void ulockprog(char *name) { char *lockfile; pid_t oldpid; FILE *fp; lockfile = calloc(PATH_MAX, sizeof(char)); snprintf(lockfile, PATH_MAX, "/var/run/%s.pid", name); if ((fp = fopen(lockfile, "r")) == NULL) { syslog(LOG_NOTICE, "Can't open lockfile `%s': %s", lockfile, strerror(errno)); free(lockfile); return; } if (fscanf(fp, "%u", &oldpid) != 1) { syslog(LOG_NOTICE, "Can't read old pid from `%s'", lockfile); fclose(fp); unlink(lockfile); free(lockfile); return; } fclose(fp); if (oldpid == getpid()) { (void)unlink(lockfile); } free(lockfile); }